Sorry, I have to disagree with your suggestion to "wiggle " the terminals.
When you do this , you cause arcing and current shock to the other components of the car's electrical systems. Now, instead of one issue, you can create others such as blown stereos, gauges, ECU's etc...
Simple easy way.
Do it right.
Remove the terminals, clean them and the battery posts and re-install them tightened properly. Coating them with a dielectric grease doesn't hurt either.